function Map(ele){
     //1 保存下地图对象
     this.ele=ele
     //2 记录地图相关属性
     this.width=800
     this.height=400
}

Map.prototype.create=function(){
    
    this.ele.style.width=this.width+'px'
    this.ele.style.height=this.height+'px'
    this.ele.style.background='url(./bg.png)'
    this.ele.style.border='10px solid green'
    this.ele.style.position='relative'
    
}

